What did Allah teach David in Surah Al-Baqarah, Verse 251?

Question

Qur'an 2:251 is as follows:

So they defeated them by permission of Allah , and David killed Goliath, and Allah gave him the kingship and prophethood and taught him from that which He willed. And if it were not for Allah checking [some] people by means of others, the earth would have been corrupted, but Allah is full of bounty to the worlds.

What exactly did Allah taught to David in this verse?

Answer 1

It's explained in other verses of Quran:

• chanting the psalms (Azzaboor), thus he is example for the perfect reciting that mountains and birds where affected by his recitation.
• Adaptation of iron and making shields
• Judging
• The most important one is he learned about Allah(knowing Allah)

(And Allah knows best).